Kirk develops valve interlock for industrial flow control applications

Kirk has developed the HD Type VL ball valve interlock to ensure that hazards such as air- and liquid-flow power must be isolated before operators or engineers can work on equipment.

The HD Type VL ball valve interlock protects against air- and liquid-flow power hazards

Air and liquid flow can present high-risk safety issues during operation and maintenance of equipment and plant. Traditionally, these sources of energy have been isolated using lockout tagout procedures. As part of a comprehensive trapped key interlocking system, the HD Type VL ensures a predetermined sequence of operations that guarantees these energy sources are isolated and mitigates the risk to personnel and plant.

The HD Type VL valve interlock comes fully assembled with the valve and is designed to fit ball valves from ¼ inch to 3 inches in diameter. The interlock is made of heavy-duty 316 stainless steel, making it suitable for washdown or harsh industrial environments, and operated through a stainless-steel lever, not the key. The HD series dowel-pin key design is gasketed, preventing debris from impeding proper operation.

The HD Type VL is intended for machine guarding of pneumatic presses, hydraulic equipment, and systems with high-pressure air. Within any industrial environment and application where it is necessary to control risk and sequential safety processes, integrating a comprehensive trapped key interlock system eliminates human error, protecting employees and preventing equipment damage.

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Kirk develops heavy-duty interlocking padlock

HD Type P improves LOTO integration with interlocking safety systems in extreme environments

Kirk has launched a new padlock that can be combined with the company’s other heavy-duty series interlocks to create a comprehensive safety system for extreme industrial environments.

The padlock is suitable for heavy industries

Developed in response to specific customer requirements, the HD Type P padlock incorporates a heavy-duty 316 stainless steel body and dowel-pin key design. The padlock features a fully-enclosed housing and gasketed key to prevent dust and debris from impeding the proper operation of the interlock. The heavy-duty design allows users to fully integrate LOTO safety procedures within an interlocking safety system in environments where standard padlocks fail.

The HD Type P is particularly suitable for industries such as mining – ensuring sequence control when de-energizing switchgear during HV coupler disconnects – as well as heavy industries like aggregates, waste and recycling, steel and chemical processing. Within any industrial environment and application where it is necessary to control risk and sequential safety processes, integrating the HD Type P and a comprehensive interlocking system guarantees the protection of employees and prevents equipment damage.

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How to make sure your data center doesn’t suffer a catastrophic power failure

Following the issues British Airways recently faced due to unauthorized disconnection and reconnection of power by an engineer at its IT facility, other organizations will be wondering how they can avoid a similar situation affecting their customers.

Trapped key interlocking systems can safeguard data center power supplies

The technology to prevent this kind of costly mistake is already widely used across the data center and switchgear industries. That technology is trapped key interlocking safety systems.

Trapped key interlocks force engineers to follow the correct process when disconnecting cables, gaining access to cabinets, powering down and powering up IT switchgear. This is achieved through interlocking keys that ensure a predetermined procedure for operations is followed in sequence, eliminating mistakes and human error. Trapped key interlocks introduce a physical barrier to switches being moved, cabinets being accessed, and cables being disconnected until it is safe, from an equipment or personnel point of view, to do so.

To further ensure that only trained and authorized personnel can begin the process of switching on, switching off, or cable disconnection, a smart key cabinet can be used in conjunction with trapped key interlocks. The smart key cabinet would retain the primary trapped key that initiates the sequence and procedures. This key can only be released by using an RFID card issued to authorized individuals. Furthermore, a smart key cabinet will track those engineers who initiated processes, record how long the key was in use, and report operational history. This information can trigger alarms to alert senior engineers and managers when keys have been released without permission or have been in use for too long.

Implementing a combination of a smart key manager and trapped key interlocks protects assets, personnel, and, as recent events have shown, the reputation of a business.

David Hughes, managing director, Kirk Key Interlock Company LLC

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Trapped Key Interlocks Protect Workers at HV Substations

Kirk access interlocks increase safety in switchgear applications, prevent arc flash
North Canton, Ohio (November 21, 2016) – KIRK interlocking products provide safe access to switchgear within HV substations. Trapped key access interlocks and key exchange units restrict physical entry and prevent dangerous operating conditions, ensuring that personnel operate equipment according to the correct sequence of operation.

Kirk Key, HV Substation

Trapped Key Interlocks prevent injury to personnel.

Trapped key interlocks prevent injury to personnel, protect equipment from damage, and assure continuity of electrical supply by initially restricting any unauthorized access. This is particularly important for HV substations located in remote, unmanned sites. Secondly, they ensure that all authorized access is done in a safe manner, requiring that part of a system is isolated and correctly earthed before maintenance can be carried out on that section.

A well-designed interlocking scheme also ensures that the system is operated correctly. This can prevent a number of dangerous scenarios such as: switching two incoming feeds onto a common bus bar, the paralleling of two energy sources, or disconnecting breakers under load. This greatly reduces the risk of fire or arc flash, protecting equipment from damage, preventing injury, and avoiding supply interruption.

For HV substation applications, Kirk recommends its HD Series interlocks. The lock housing, cylinder, and inner workings are manufactured entirely of 316 stainless steel. A robust dowel pin key design resists breakage and prevents duplication. A gasketed flip cover protects the keyways from debris. The HD Series range includes mechanical and electromechanical bolt, access, transfer, and valve interlocks, along with a full range of accessories to form a comprehensive switchgear interlocking scheme for HV substations.


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Kirk Key Interlock Debuts CAD Model Database

Trapped key interlocking models to aid in engineering design projects
North Canton, Ohio (March 16, 2016) – Kirk Key Interlock has launched a new CAD Model database through their website at The new database design allows registered users to download 2D and 3D models of KIRK® products for use by engineers during the design process to check for clearance and mounting options.


The database provides a comprehensive menu of KIRK® products. Registered users can search through the menu, find their specific product needs, view an image of the product chosen, and download the 2D and 3D files.

The link to the CAD Model database can be found on the homepage of the Kirk Key website at under the Quick Links section. Also, with the launch of this database, a newly update website page titled Customer Portal is home to additional product and application downloads, ordering & shipment information, and more.

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Kirk Produces New Application Data Sheet For Emergency Power Tap Box Applications

North Canton, Ohio (October 28, 2016) – Kirk Key Interlock has launched a data sheet explaining how to safely restore power via an emergency generator when a facility’s main power has been lost.

Kirk has launched a data sheet explaining how to safely restore power via an emergency generator when a facility’s main power has been lost

An installed tap box, equipped with KIRK® trapped key interlocks, offers a lower-cost manual transfer alternative to automatic transfer systems, and can reinstate operations with minimal time and dollars lost.

KIRK® key interlocks ensure that a predetermined sequence of operations is performed to prevent crucial safety measures from being omitted while restoring power. KIRK® key interlocks can be installed in the field to existing / previously-installed tap boxes, often without interrupting power. Once installed, the power restoration process can be implemented safely during lost power situations.

The data sheet can be accessed here.

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Kirk Develops Nonlinear Transfer Unit

Offering opportunities for interlocking safety systems within nonlinear sequences
North Canton, Ohio (March 30, 2016) – Kirk Key has developed a trapped key interlock transfer unit to provide safety interlock provisions for trapped key interlocking systems requiring nonlinear sequences. The Type NLTU (Nonlinear Transfer Unit) can be implemented in typical applications such as purging of gases, which requires a nonlinear sequenced process with valve interlocks, to purge gases safely & drive a predetermined non-linear sequence of operations.

Kirk Key, trapped key interlock

Kirk Key has developed a trapped key interlock transfer unit

The Type NLTU incorporates a selector designed and manufactured to customer specified operational requirements. This unit can be manufactured with up to 8 cylinders; 8 non-linear sequenced steps. The unit has a lamacoid affixed to the side of the aluminum housing providing details about the sequenced steps within the operation and the desired action for each step throughout the process.

The Type NLTU is available in the SD Series (Standard Duty – Brass) and HD Series (Heavy Duty – Stainless Steel). As with Kirk’s line of transfer interlocks and panels, the Type NLTU is able to exchange keys across both series enabling the transfer of keys across interlocking systems as required within a process.

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Kirk Key Interlock Safeguards Small Circuit Breakers

Smaller footprint bolt lock offers greater product options for switchgear applications
North Canton, Ohio (April 7, 2015) – Kirk Key has developed a reduced size mechanical bolt interlock for smaller stature breakers. Modelled on the KIRK Standard Duty series Type F, the smaller Type FF ensures that workers follow a pre-determined sequence of operation to safely access electrical switchgear. Manufactured with a brass lock housing and cylinder, the Type FF has a ¾” travel, with a smaller diameter ½” stainless steel lock bolt to better fit in smaller cabinets. The proprietary 7-pin tumbler key design is unique to Kirk and not available commercially, minimizing the risk of circumventing safety sequences with duplicate keys.

Kirk Key Type FF

Kirk Key Type FF reduced size mechanical bolt interlock for smaller circuit breakers.

The Type FF footprint is 2”x1¼” and is generally flat or face mounted with ¼” mounting bolts through the front of the housing. The reduced footprint of the Type FF is approximately 50 percent smaller and nearly 60 percent lighter, allowing for greater clearance around the breaker within the switchgear assembly.

The Type FF, in conjunction with Kirk’s current comprehensive line of Standard Duty bolt, electro-mechanical, access, transfer, and cylinder interlocks, creates a complete trapped key interlock system for switchgear and other process safety applications.

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KIRK Interlocks Debuts New Website

Trapped key interlocking information and products easy to find at  
North Canton, Ohio (March 4, 2015) – KIRK® has launched a redesigned website at The all new site design helps users more easily navigate through trapped key interlocking product and educational information with application specific pages, standards information, and a customer portal.

The new

The site’s new Applications section provides comprehensive information on trapped key interlock use in switchgear, electrostatic precipitators, flow control, ports, perimeter guarding, and other applications. In addition to a general overview, application pages include animations, typical scheme examples, and links to relevant product detail.

The Customer Portal section provides important information on how-to order and a tab for downloads that includes relevant forms, data sheets, and manuals. A secure link to Kirk’s Customer Portal login page provides order status for both open and closed purchase orders, along with order shipping and tracking information.

For quick reference, Kirk provides relevant OSHA, ANSI, IEEE, NEC, and NFPA standards/regulations information for its US customers and MTE regulations for its Brazilian users.

To learn more about Kirk and trapped key interlocking, visit the new

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KIRK Interlocks Safeguard Alternative Maritime Power Connections

Trapped key interlocks increase safety of electrical connections in shore power applications
North Canton, Ohio (January 29, 2015) – KIRK® interlocking products provide safe electrical access during cold ironing, ensuring that ship power cables are properly coupled to shore power junction boxes before energizing. Trapped key access interlocks and key exchange units ensure that users follow a pre-determined sequence of operation when connecting to land based power while in port.

Alternative Marine Power AMP safety

KIRK® interlocking products provide safe electrical access during cold ironing.

In a typical shore power interlocking scheme, a ship’s AMP cable reel is fitted with Kirk’s type DM latch bolts on the shore power plug. The corresponding type DM access interlocks are installed on the junction box’s voltage socket handles inside the quayside vault. A 3-key Kirk transfer block is also installed directly on the front of the junction box. Finally, the upstream breakers powering the junction box are fitted with a Kirk F-lock, keyed to coordinate with the transfer block.

To connect to shore power, the AMP cable is lowered to the wharf. Once both plugs are connected, the two DM latch bolts are inserted into the DM locks. This allows the locks to be engaged, securing the plugs in place and releasing a key for each socket. The two socket keys are then inserted into the transfer block, releasing the third key, used to energize the upstream power. This power key remains trapped in place the entire time the system is energized.

There is no way to circumvent the process; the junction box cannot be energized without first properly connecting the sockets. The socket connection then cannot be broken until the upstream power is shut off, releasing the key required by the transfer block in order to access the two socket release keys.

For cold ironing applications, Kirk recommends its HD Series interlocks. All lock components are manufactured entirely of 316 stainless steel for long service life in corrosive coastal environments. A gasketed flip cover further protects the keyways from salt and debris intrusion.

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